Using oxalic acid as a standard for chemical oxygen demand determination with closed reflux–colorimetric method
Vol. 130 No. 1C (2021), Original Article
Vol. 130 No. 1C (2021)

Using oxalic acid as a standard for chemical oxygen demand determination with closed reflux–colorimetric method

Original Article
https://doi.org/10.26459/hueunijns.v130i1C.6358
Published 2021-07-05
Hoang Thai Long*
Department of Chemistry, University of Sciences, Hue University, 77 Nguyen Hue St., Hue, Vietnam
Nguyen Sy Bao
Department of Chemistry, University of Sciences, Hue University, 77 Nguyen Hue St., Hue, Vietnam
Ta Thi Kim Dung
International Education City – IEC Quang Ngai, 230 Truong Chinh, Nghia Lo Ward, Quang Ngai City, Vietnam
PDF (Vietnamese)

Keywords

nhu cầu oxi hóa học, COD, kali hydro phthalate, KHP, axit oxalic nhu cầu oxi hóa học
COD
kali hydro phthalate
KHP
axit oxalic
chemical oxygen demand

How to Cite

1.
Long HT, Bảo NS, Dung TTK. Using oxalic acid as a standard for chemical oxygen demand determination with closed reflux–colorimetric method. hueuni-jns [Internet]. 2021Jul.5 [cited 2024Dec.28];130(1C):23-30. Available from: https://jos.hueuni.edu.vn/index.php/hujos-ns/article/view/6358
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Abstract

Potassium hydrogen phthalate (KHP) is used as a standard to determine the chemical oxygen demand (COD) with the closed reflux-colourimetric method (colourimetric method). Besides KHP, it is possible to utilize oxalic acid for this purpose. After boiling at 150 °C for more than 30 minutes in H2SO4 containing Ag2SO4, K2Cr2O7 reacts completely with H2C2O4 at a molar ratio of 1:3. The experimentally determined chemical oxygen demand of H2C2O4 coincides with its theoretical value at 16.0 mg O2/mole H2C2O4. The average COD values of two river water samples, determined with the colourimetric method by using KHP standard and oxalic acid, are not statistically different. Oxalic acid can be used as a standard to determine COD with the colourimetric method.

https://doi.org/10.26459/hueunijns.v130i1C.6358
PDF (Vietnamese)

References

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